Retractable screens that can be opened have found appeal with users due to their versatility in being able to be rolled up when not in use. This enables a wide and uninterrupted view when withdrawn. The present invention will be described with particular reference to insect screen mesh. However, it will be appreciated that the invention may relate to other types of flexible screen material and no limitation is intended thereby.
Retractable screens can be mounted across any suitable architectural opening such as windows, doors, and between supports in outdoor areas such as pergolas, gazebos and the like. Retractable screens are generally insect screens. However, other types of screens such as UV or screens or the like may also be retractable.
Retractable screens in general having a roller located within a housing, upon which the screen is rolled onto as the screen is closed and the screen is unrolled from when the screen is opened. The roller is usually biased towards the closed or rolled up position. The housing is typically fixed in place at the top of a vertically opening screen or at the side of a horizontally opening screen. The screen extends between the housing and a moveable handle post that is moveable between an open position towards the housing and a closed position away from the housing. Upper and lower, or right and left guide rails or tracks (for horizontally and vertically opening windows) are operatively engaged with the respective ends of the moveable handle post to guide movement of the post between open and closed positions.
Alternatively, the housing may be located within the moveable handle post, although this is not as preferred for larger screens.
It is important, especially for insect screens, that the edges of the screen are securely held in place such that there are no gaps through which insects may pass. It is also desirable for the screen to have a taut and neat appearance across the face of the screen. Suitably, the longitudinal edges of the screens are retained within a channel in the respective guide tracks and the transverse edge is securely held along the length of the moveable handle post (or housing as the case may be).
In use, a retractable screen is subjected to forces caused by the tautness of the screen such that the screen may pull out of the guide tracks and become loose. This is undesirable for customers. Further, this can create gaps through which insects may pass. When closed, the screens may be subjected to winds that can cause the screen to “blow out” of the guide tracks. To avoid “blow out”, the screen receiving channels in the guide tracks and/or the edges of the screen are arranged so that they are securely received therein. The desirability for the screen to be securely held so as to resist “blow out” must be balanced with the ability of the longitudinal edges of the screen to be able to readily slide along the tracks during opening and closing.
Horizontally opening screens can pose problems that are not found with vertically opening screens. As customers are demanding horizontally opening screens of increasing width, the size and weight of the screen increases. The design of the roller and guide tracks must accommodate the increased weight. Weight is less of an issue with vertically opening screens as the roller is at the top and supports the weight of the screen as it opens and closes. The guide tracks simply guide the path of the screen. However, with horizontally opening screens, the weight of the screen must be shared by the guide tracks. The increase in weight, especially borne by the upper guide track can increase the likelihood of blow out. There is accordingly much interest in the retractable screen industry to provide a screen that may alleviate this disadvantage.
One attempt to address the problem of “blow out” has been to provide the screen with a thickened longitudinal edge that is retained within a channel in the guide rail. However, whilst such an arrangement is suitable up to a certain size and weight of a screen, for screens of increasing size and weight, the risk of blow out or malfunction increases.
With vertically opening screens, it is common to use a screen having an edge with a zipper tape heat welded along its longitudinal edge. The zipper is a conventional coil zipper. Coil zippers have teeth formed from a continuous coil of polyester or nylon wound onto a tape. The zipper tape is easily cut to size and is flexible and can be rolled and unrolled. When the tape is welded to a flexible screen, the zipper edge may be securely retained within a retaining channel. The advantages of using a zipper tape as a means of retaining a retractable screen within a vertical guide track having a suitable retaining channel is well known. A further advantage is that the teeth are able to slide smoothly along or within an extruded aluminium guide track.
However, what is also well known is that retractable screens having a zipper tape edge are unsuitable for use on horizontally opening screens. With vertically opening screens, the screens are uniformly rolled onto the roller. When rolled on the roller the weight of the screen is distributed evenly across the roller. In other words, when rolled, the edges of the screen are always in suitable alignment with the guide tracks. This may be compared to horizontally opening screens in which the roller is in a vertical position. In this case, the weight of the screen causes the screen to roll unevenly and/or sag due to its weight. This is exacerbated with increasing weight of the screen. The edge of the screen is therefore often not in correct alignment with the guide track. This is of little consequence when the edge of the screen is continuous such as a thickened edge. However, in the case of a discontinuous edge, such as in the case of a zipper edge having separated teeth, the edge is subject to being caught up as it exits the housing and enters the retaining channel of the guide track. Also entering the retaining channel at an angle can cause the teeth to slip from the channel.
The present invention it therefore directed towards providing a horizontally opening retractable screen in which the screen has toothed edges.